Export to excel not working when using Ajax in MVC - asp.net

Hi i have created export class that converts Gridview to excel file.
See below code:
DownloadFileActionResult Class:
public class DownloadFileActionResult : ActionResult
{
public GridView ExcelGridView { get; set; }
public string fileName { get; set; }
public DownloadFileActionResult(GridView gv, string pFileName)
{
ExcelGridView = gv;
fileName = pFileName;
}
public override void ExecuteResult(ControllerContext context)
{
HttpContext curContext = HttpContext.Current;
curContext.Response.ClearContent();
curContext.Response.AddHeader("content-disposition", "attachment; filename=" + fileName + ".xls");
curContext.Response.ContentType = "application/vnd.ms-excel";
StringWriter sw = new StringWriter();
HtmlTextWriter htw = new HtmlTextWriter(sw);
ExcelGridView.RenderControl(htw);
curContext.Response.Write(sw.ToString());
curContext.Response.End();
}
}
Jquery-ajax:
function Export(){
var search = {};
search.Name = "MaterialShape";
search.Description = "";
search.Address ="";
var url_ = generateURL("/Home/Download"); //Call Save Controller and pass details entities
$.ajax({
type: "POST",
url: url_,
data: search, //details will act as the Entities Model
traditional: true,
success: function(data) {
},
error: function(XMLHttpRequest, textStatus, errorThrown) {
alert("error: " + XMLHttpRequest.responseText);
},
dataType: 'json'
});
};
Search Parmeter Properties:
public class SearchParams
{
public string Name{ get; set; }
public string Description {get;set;}
public string Address{get;set;}
...
}
And then i implement it on my controller:
//Export to excel
public ActionResult Download(SearchParam param)
{
List<Lookup> lookupList = data.GetLookup(param);
var grid = new System.Web.UI.WebControls.GridView();
grid.DataSource = lookupList;
grid.DataBind();
return new DownloadFileActionResult(grid, "test");
}
It is working(without search param values) when i type the controller url manually
http://localhost:54928/Home/Download
or using html.action link
<%= Html.ActionLink("Home", "/Download", "Home")%>
but it is not working when i use ajax call
<img src="<%=Url.Content("~/Images/export.png")%>" id="Img1" onclick="Export();" alt="Export" />
that i really need to use.
I am missing something here..any ideas?
Thanks in Regards

It does not make sense to use $.ajax to download excel file - the ajax call is really meant to get text-based data (html. xml, JSON) in your js code so that you can work with it. Browser knows how to handle (e.g. prompt for saving the file) the binary content such as excel.
In this case, all you need to is a simple POST/GET request to initiate the excel file download (as simple as document.location = "/home/download?q=keyword";)

Related

Manipulating the received Json Data in Web API Controller

I am passing Json Data from Angular JS Controller. The Json Data contains two strings called name attribute and comment attribute and a list of files. The controller code for angular is given below:
app.controller("demoController", function ($scope, $http) {
//1. Used to list all selected files
$scope.files = [];
//2. a simple model that want to pass to Web API along with selected files
$scope.jsonData = {
name: "Sibnz",
comments: "This is a comment"
};
//3. listen for the file selected event which is raised from directive
$scope.$on("seletedFile", function (event, args) {
$scope.$apply(function () {
//add the file object to the scope's files collection
$scope.files.push(args.file);
});
});
//4. Post data and selected files.
$scope.save = function () {
$http({
method: 'POST',
url: "http://localhost:51739/PostFileWithData",
headers: { 'Content-Type': undefined },
transformRequest: function (data) {
var formData = new FormData();
formData.append("model", angular.toJson(data.model));
for (var i = 0; i < data.files.length; i++) {
formData.append("file" + i, data.files[i]);
}
return formData;
},
data: { model: $scope.jsonData, files: $scope.files }
}).
success(function (data, status, headers, config) {
alert("success!");
}).
error(function (data, status, headers, config) {
alert("failed!");
});
};
});
In the Web API, controller I am receiving the JSON data by using the following code:
[HttpPost]
[Route("PostFileWithData")]
public async Task<HttpResponseMessage> Post()
{
if (!Request.Content.IsMimeMultipartContent())
{
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}
var root = HttpContext.Current.Server.MapPath("~/App_Data/Uploadfiles");
Directory.CreateDirectory(root);
var provider = new MultipartFormDataStreamProvider(root);
var result = await Request.Content.ReadAsMultipartAsync(provider);
var model = result.FormData["jsonData"];
var g = result.FileData;
if (model == null)
{
throw new HttpResponseException(HttpStatusCode.BadRequest);
}
//TODO: Do something with the JSON data.
//get the posted files
foreach (var file in result.FileData)
{
//TODO: Do something with uploaded file.
var f = file;
}
return Request.CreateResponse(HttpStatusCode.OK, "success!");
}
When I debug the code, I find that the JSON data is populating the var model and var g variables. I want to extract the name and comment attributes from the Json Data and store them in the Database. And also want to copy the file into /App_Data/Uploadfiles directory and store the file location in the database.
You need to create a model in your Web API and deserialize JSON data to this model, you can use Newtonsoft.Json NuGet package for that
Install-Package Newtonsoft.Json
class DataModel
{
public string name { get; set; }
public string comments { get; set; }
}
In Web API controller
using Newtonsoft.Json;
HttpRequest request = HttpContext.Current.Request;
var model = JsonConvert.DeserializeObject<DataModel>(request.Form["jsonData"]);
// work with JSON data
model.name
model.comments
To work with files
// Get the posted files
if (request.Files.Count > 0)
{
for (int i = 0; i < request.Files.Count; i++)
{
Stream fileStream = request.Files[i].InputStream;
Byte[] fileBytes = new Byte[stampStream.Length];
// Do something with uploaded file
var root = HttpContext.Current.Server.MapPath("~/App_Data/Uploadfiles/");
string fileName = "image.jpg";
File.WriteAllBytes(root + fileName, stampBytes);
// Save only file name to your database
}
}

How to use parameters in Twitter Bootstrap loaded dynamically from the database

I have a website where I need multiple themes.
So www.mysite.com/Client1/ uses red buttons and www.mysite.com/Client2/ uses blue buttons.
The number of clients are dynamic stores in a DB, and the colors are also stored in the DB. Can be changed at anytime by the client.
Currently I am using Twitter Bootstrap LESS files and ASP MVC Optimization (bundle).
My App_Start BundleConfig looks like this:
var cssTransformer = new CssTransformer();
var stylesBundle = new StyleBundle("~/Content/bootstrap");
.Include("~/Content/less/bootstrap.less")
stylesBundle.Transforms.Add(cssTransformer);
bundles.Add(stylesBundle);
In variables.less
#btnPrimaryBackground: #linkColor;
The color of #btnPrimaryBackground should change when different urls are called.
How do I change the less variable to use a parameter from my another source (database or other)?
Since Web Optimization does not play nice with dynamic dontent, I decided to not use it.
Instead I have made am ASP MVC ActionResult for LESS, and reference that.
<link rel="stylesheet" type="text/css" href="#Url.Action("Styles", "Theme")">
My ASP MVC Controller looks like this:
public class ThemeController : Controller
{
public ActionResult Styles()
{
var parameters = new Dictionary<string, string>
{
{"themeColor1", "Get theme color 1 here"},
{"themeColor2", "Get theme color 2 here"}
};
var themeLessFilePath = Server.MapPath("~/Content/less/theme.less");
using (var stream = System.IO.File.OpenRead(themeLessFilePath))
{
return new DotLessResult(stream, parameters, true);
}
}
}
And the LESS ActionResult like this:
public class DotLessResult : ActionResult
{
public IDictionary<string, string> Parameters { get; set; }
public string Less { get; set; }
public bool Minify { get; set; }
public DotLessResult(string less, IDictionary<string, string> parameters = null, bool minify = false)
{
Less = less;
Parameters = parameters ?? new Dictionary<string, string>();
Minify = minify;
}
public DotLessResult(Stream stream, IDictionary<string, string> parameters = null, bool minify = false)
: this(new StreamReader(stream).ReadToEnd(), parameters, minify) { }
public override void ExecuteResult(ControllerContext context)
{
var output = Less;
//TODO: Not the way to do this!
foreach (var key in Parameters.Keys)
{
output = Regex.Replace(output, #"#" + key + #":\s*\S+;", "#" + key + ":" + Parameters[key] + ";");
}
var lessEngine = dotless.Core.LessWeb.GetEngine(new DotlessConfiguration { MinifyOutput = Minify, MapPathsToWeb = true, Web = true, CacheEnabled = false});
var css = lessEngine.TransformToCss(output, (string)null);
context.HttpContext.Response.ContentType = "text/css";
using (var writer = new StreamWriter(context.HttpContext.Response.OutputStream, Encoding.UTF8))
{
writer.Write(css);
writer.Flush();
}
}
}
Its NOT the best solution, but it works on my machine TM.
Dont forget to implement some kind of output caching as it will most like be hit alot, and not change very often.

json object and Web method Invalid Web services call missing value parameter

I have Jquery sortable UI I have web services to update the order of reminder when user update the reminder orders I know it is problem passing json data to web services but could not solve it
Error:
Invalid Web services call missing value parameter: rlist
at System.Web.Script.Services.WebServiceMethodData.CallMethod(Object target, IDictionary2 parameters)
at System.Web.Script.Services.WebServiceMethodData.CallMethodFromRawParams(Object target, IDictionary2 parameters)
at System.Web.Script.Services.RestHandler.InvokeMethod(HttpContext context, WebServiceMethodData methodData, IDictionary`2 rawParams)
at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)
Web Services
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using Compudata_ProjectManager.CodeFile.BOL;
using System.Data.SqlClient;
using System.Web.Script.Services;
namespace Compudata_ProjectManager.WebServices
{
/// <summary>
/// Summary description for remindersWebService
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
[ScriptService]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
// [System.Web.Script.Services.ScriptService]
public class remindersWebService : System.Web.Services.WebService
{
public class ReminderDTO
{
public int Id { get; set; }
public int Order { get; set; }
}
[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public string UpdateOrder(List<ReminderDTO> rList)
{
//CompuData_ProjectManagerConfiguration.DbconnctionString;
using (SqlConnection connectionString = new SqlConnection(CompuData_ProjectManagerConfiguration.DbconnctionString))
{
foreach (var r in rList)
{
string sSQL = "UPDATE [TaskManagementSystem_DB].[dbo].[Reminders] SET [reminderOrder] = " + r.Order.ToString() + "where reminderID = " + r.Id;
SqlCommand cmd = new SqlCommand(sSQL, connectionString);
try
{
cmd.ExecuteNonQuery();
}
catch (SqlException)
{
return "falied";
}
}
return "save";
}
}
}
}
javascript
$(function () {
$("#sortable").sortable({
placeholder: "vacant",
update: function (e, ui) {
//process each li
//create vars
var orderArray = [];
var wrap = {};
$("#sortable li").each(function () {
//build ReminderObject
var reminderObject = {
Id: $(this).attr("id"),
Order: $(this).find("input[type='hidden']").val()
};
//add object to array
orderArray.push(reminderObject);
});
wrap.d = orderArray
//pass to server
$.ajax({
type: "POST",
url: "../WebServices/remindersWebService.asmx/UpdateOrder",
data: JSON.stringify(wrap),
processData: false,
contentType: "application/json; charset=utf-8",
success: function (data) {
if (data.d === "saved") {
document.write("Save ok");
} else {
document.write("Save failed");
}
},
error: function (xhr, status, error) {
var err = eval("(" + xhr.responseText + ")");
console.log(err.StackTrace);
alert(err.Message);
}
});
} //end of update function
});
$("#sortable").disableSelection();
$("input[type=checkbox]").on("click", function () {
$(this).nextAll().toggleClass("hidden");
});
});
</script>
Try sending Id and Order as integers as they are expected to be.
var reminderObject = {
Id: parseInt($(this).attr("id"), 10),
Order: parseInt($(this).find("input[type='hidden']").val(), 10)
};
Also change wrap.d = orderArray to wrap.rList = orderArray as rList is the expected parameter.

Using Url.Content() when sending an html email with images

I need my app to send a confirmation email to a user. I have used the following method to render the view as a string:
public string RenderViewToString<T>(string viewPath, T model)
{
using (var writer = new StringWriter())
{
var view = new WebFormView(viewPath);
var vdd = new ViewDataDictionary<T>(model);
var viewCxt = new ViewContext(ControllerContext, view, vdd, new TempDataDictionary(), writer);
viewCxt.View.Render(viewCxt, writer);
return writer.ToString();
}
}
which I got from here. It works great, however my images aren't being included. I'm using:
<img src="<%:Url.Content("~/Resource/confirmation-email/imageName.png") %>"
which is giving me
http://resource/confirmation-email/imageName.png
This works fine when viewing the page on the site, however the image links don't work in the email.
I need it to give me me:
http://domain.com/application/resource/confirmation-email/imageName.png
I've also tried using:
VirtualPathUtility.ToAbsolute()
This is what I used on a site recently:
public static string ResolveServerUrl(string serverUrl, bool forceHttps = false, bool getVirtualPath = true)
{
if (getVirtualPath)
serverUrl = VirtualPathUtility.ToAbsolute(serverUrl);
if (serverUrl.IndexOf("://") > -1)
return serverUrl;
string newUrl = serverUrl;
Uri originalUri = System.Web.HttpContext.Current.Request.Url;
newUrl = (forceHttps ? "https" : originalUri.Scheme) + "://" + originalUri.Authority + newUrl;
return newUrl;
}
I could then use it to generate Absolute urls by doing Core.ResolveServerUrl("~/Resource/confirmation-email/imageName.png"); (assuming you wrap the static function in a class named Core)
HTH
There isn't a way to do this. You can add the following extension method.
using System.Web.Mvc;
public static class UrlHelperExtensions
{
public static string ToAbsoluteUrl(this UrlHelper helper, string relativeUrl) {
if (Request.IsSecureConnection)
return string.Format("https://{0}{1}", Request.Url.Host, Page.ResolveUrl(relativeUrl));
else
return string.Format("http://{0}{1}", Request.Url.Host, Page.ResolveUrl(relativeUrl));
}
}
Which you can then call like so
<img src="<%:Url.ToAbsoluteUrl("~/Resource/confirmation-email/imageName.png") %>" ...

Can an ASP.NET MVC controller return an Image?

Can I create a Controller that simply returns an image asset?
I would like to route this logic through a controller, whenever a URL such as the following is requested:
www.mywebsite.com/resource/image/topbanner
The controller will look up topbanner.png and send that image directly back to the client.
I've seen examples of this where you have to create a View - I don't want to use a View. I want to do it all with just the Controller.
Is this possible?
Use the base controllers File method.
public ActionResult Image(string id)
{
var dir = Server.MapPath("/Images");
var path = Path.Combine(dir, id + ".jpg"); //validate the path for security or use other means to generate the path.
return base.File(path, "image/jpeg");
}
As a note, this seems to be fairly efficient. I did a test where I requested the image through the controller (http://localhost/MyController/Image/MyImage) and through the direct URL (http://localhost/Images/MyImage.jpg) and the results were:
MVC: 7.6 milliseconds per photo
Direct: 6.7 milliseconds per photo
Note: this is the average time of a request. The average was calculated by making thousands of requests on the local machine, so the totals should not include network latency or bandwidth issues.
Using the release version of MVC, here is what I do:
[AcceptVerbs(HttpVerbs.Get)]
[OutputCache(CacheProfile = "CustomerImages")]
public FileResult Show(int customerId, string imageName)
{
var path = string.Concat(ConfigData.ImagesDirectory, customerId, "\\", imageName);
return new FileStreamResult(new FileStream(path, FileMode.Open), "image/jpeg");
}
I obviously have some application specific stuff in here regarding the path construction, but the returning of the FileStreamResult is nice and simple.
I did some performance testing in regards to this action against your everyday call to the image (bypassing the controller) and the difference between the averages was only about 3 milliseconds (controller avg was 68ms, non-controller was 65ms).
I had tried some of the other methods mentioned in answers here and the performance hit was much more dramatic... several of the solutions responses were as much as 6x the non-controller (other controllers avg 340ms, non-controller 65ms).
To expland on Dyland's response slightly:
Three classes implement the FileResult class:
System.Web.Mvc.FileResult
System.Web.Mvc.FileContentResult
System.Web.Mvc.FilePathResult
System.Web.Mvc.FileStreamResult
They're all fairly self explanatory:
For file path downloads where the file exists on disk, use FilePathResult - this is the easiest way and avoids you having to use Streams.
For byte[] arrays (akin to Response.BinaryWrite), use FileContentResult.
For byte[] arrays where you want the file to download (content-disposition: attachment), use FileStreamResult in a similar way to below, but with a MemoryStream and using GetBuffer().
For Streams use FileStreamResult. It's called a FileStreamResult but it takes a Stream so I'd guess it works with a MemoryStream.
Below is an example of using the content-disposition technique (not tested):
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult GetFile()
{
// No need to dispose the stream, MVC does it for you
string path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "App_Data", "myimage.png");
FileStream stream = new FileStream(path, FileMode.Open);
FileStreamResult result = new FileStreamResult(stream, "image/png");
result.FileDownloadName = "image.png";
return result;
}
This might be helpful if you'd like to modify the image before returning it:
public ActionResult GetModifiedImage()
{
Image image = Image.FromFile(Path.Combine(Server.MapPath("/Content/images"), "image.png"));
using (Graphics g = Graphics.FromImage(image))
{
// do something with the Graphics (eg. write "Hello World!")
string text = "Hello World!";
// Create font and brush.
Font drawFont = new Font("Arial", 10);
SolidBrush drawBrush = new SolidBrush(Color.Black);
// Create point for upper-left corner of drawing.
PointF stringPoint = new PointF(0, 0);
g.DrawString(text, drawFont, drawBrush, stringPoint);
}
MemoryStream ms = new MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
return File(ms.ToArray(), "image/png");
}
You can create your own extension and do this way.
public static class ImageResultHelper
{
public static string Image<T>(this HtmlHelper helper, Expression<Action<T>> action, int width, int height)
where T : Controller
{
return ImageResultHelper.Image<T>(helper, action, width, height, "");
}
public static string Image<T>(this HtmlHelper helper, Expression<Action<T>> action, int width, int height, string alt)
where T : Controller
{
var expression = action.Body as MethodCallExpression;
string actionMethodName = string.Empty;
if (expression != null)
{
actionMethodName = expression.Method.Name;
}
string url = new UrlHelper(helper.ViewContext.RequestContext, helper.RouteCollection).Action(actionMethodName, typeof(T).Name.Remove(typeof(T).Name.IndexOf("Controller"))).ToString();
//string url = LinkBuilder.BuildUrlFromExpression<T>(helper.ViewContext.RequestContext, helper.RouteCollection, action);
return string.Format("<img src=\"{0}\" width=\"{1}\" height=\"{2}\" alt=\"{3}\" />", url, width, height, alt);
}
}
public class ImageResult : ActionResult
{
public ImageResult() { }
public Image Image { get; set; }
public ImageFormat ImageFormat { get; set; }
public override void ExecuteResult(ControllerContext context)
{
// verify properties
if (Image == null)
{
throw new ArgumentNullException("Image");
}
if (ImageFormat == null)
{
throw new ArgumentNullException("ImageFormat");
}
// output
context.HttpContext.Response.Clear();
context.HttpContext.Response.ContentType = GetMimeType(ImageFormat);
Image.Save(context.HttpContext.Response.OutputStream, ImageFormat);
}
private static string GetMimeType(ImageFormat imageFormat)
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
return codecs.First(codec => codec.FormatID == imageFormat.Guid).MimeType;
}
}
public ActionResult Index()
{
return new ImageResult { Image = image, ImageFormat = ImageFormat.Jpeg };
}
<%=Html.Image<CapchaController>(c => c.Index(), 120, 30, "Current time")%>
Why not go simple and use the tilde ~ operator?
public FileResult TopBanner() {
return File("~/Content/images/topbanner.png", "image/png");
}
You can write directly to the response but then it isn't testable. It is preferred to return an ActionResult that has deferred execution. Here is my resusable StreamResult:
public class StreamResult : ViewResult
{
public Stream Stream { get; set; }
public string ContentType { get; set; }
public string ETag { get; set; }
public override void ExecuteResult(ControllerContext context)
{
context.HttpContext.Response.ContentType = ContentType;
if (ETag != null) context.HttpContext.Response.AddHeader("ETag", ETag);
const int size = 4096;
byte[] bytes = new byte[size];
int numBytes;
while ((numBytes = Stream.Read(bytes, 0, size)) > 0)
context.HttpContext.Response.OutputStream.Write(bytes, 0, numBytes);
}
}
Below code utilizes System.Drawing.Bitmap to load the image.
using System.Drawing;
using System.Drawing.Imaging;
public IActionResult Get()
{
string filename = "Image/test.jpg";
var bitmap = new Bitmap(filename);
var ms = new System.IO.MemoryStream();
bitmap.Save(ms, ImageFormat.Jpeg);
ms.Position = 0;
return new FileStreamResult(ms, "image/jpeg");
}
UPDATE: There are better options than my original answer. This works outside of MVC quite well but it's better to stick with the built-in methods of returning image content. See up-voted answers.
You certainly can. Try out these steps:
Load the image from disk in to a byte array
cache the image in the case you expect more requests for the image and don't want the disk I/O (my sample doesn't cache it below)
Change the mime type via the Response.ContentType
Response.BinaryWrite out the image byte array
Here's some sample code:
string pathToFile = #"C:\Documents and Settings\some_path.jpg";
byte[] imageData = File.ReadAllBytes(pathToFile);
Response.ContentType = "image/jpg";
Response.BinaryWrite(imageData);
Hope that helps!
Solution 1: To render an image in a view from an image URL
You can create your own extension method:
public static MvcHtmlString Image(this HtmlHelper helper,string imageUrl)
{
string tag = "<img src='{0}'/>";
tag = string.Format(tag,imageUrl);
return MvcHtmlString.Create(tag);
}
Then use it like:
#Html.Image(#Model.ImagePath);
Solution 2: To render image from database
Create a controller method that returns image data like below
public sealed class ImageController : Controller
{
public ActionResult View(string id)
{
var image = _images.LoadImage(id); //Pull image from the database.
if (image == null)
return HttpNotFound();
return File(image.Data, image.Mime);
}
}
And use it in a view like:
# { Html.RenderAction("View","Image",new {id=#Model.ImageId})}
To use an image rendered from this actionresult in any HTML, use
<img src="http://something.com/image/view?id={imageid}>
This worked for me.
Since I'm storing images on a SQL Server database.
[HttpGet("/image/{uuid}")]
public IActionResult GetImageFile(string uuid) {
ActionResult actionResult = new NotFoundResult();
var fileImage = _db.ImageFiles.Find(uuid);
if (fileImage != null) {
actionResult = new FileContentResult(fileImage.Data,
fileImage.ContentType);
}
return actionResult;
}
In the snippet above _db.ImageFiles.Find(uuid) is searching for the image file record in the db (EF context). It returns a FileImage object which is just a custom class I made for the model and then uses it as FileContentResult.
public class FileImage {
public string Uuid { get; set; }
public byte[] Data { get; set; }
public string ContentType { get; set; }
}
you can use File to return a file like View, Content etc
public ActionResult PrintDocInfo(string Attachment)
{
string test = Attachment;
if (test != string.Empty || test != "" || test != null)
{
string filename = Attachment.Split('\\').Last();
string filepath = Attachment;
byte[] filedata = System.IO.File.ReadAllBytes(Attachment);
string contentType = MimeMapping.GetMimeMapping(Attachment);
System.Net.Mime.ContentDisposition cd = new System.Net.Mime.ContentDisposition
{
FileName = filename,
Inline = true,
};
Response.AppendHeader("Content-Disposition", cd.ToString());
return File(filedata, contentType);
}
else { return Content("<h3> Patient Clinical Document Not Uploaded</h3>"); }
}
Look at ContentResult. This returns a string, but can be used to make your own BinaryResult-like class.
if (!System.IO.File.Exists(filePath))
return SomeHelper.EmptyImageResult(); // preventing JSON GET/POST exception
else
return new FilePathResult(filePath, contentType);
SomeHelper.EmptyImageResult() should return FileResult with existing image (1x1 transparent, for example).
This is easiest way if you have files stored on local drive.
If files are byte[] or stream - then use FileContentResult or FileStreamResult as Dylan suggested.
I see two options:
1) Implement your own IViewEngine and set the ViewEngine property of the Controller you are using to your ImageViewEngine in your desired "image" method.
2) Use a view :-). Just change the content type etc.
You could use the HttpContext.Response and directly write the content to it (WriteFile() might work for you) and then return ContentResult from your action instead of ActionResult.
Disclaimer: I have not tried this, it's based on looking at the available APIs. :-)
I also encountered similar requirement,
So in my case I make a request to Controller with the image folder path, which in return sends back a ImageResult object.
Following code snippet illustrate the work:
var src = string.Format("/GenericGrid.mvc/DocumentPreviewImageLink?fullpath={0}&routingId={1}&siteCode={2}", fullFilePath, metaInfo.RoutingId, da.SiteCode);
if (enlarged)
result = "<a class='thumbnail' href='#thumb'>" +
"<img src='" + src + "' height='66px' border='0' />" +
"<span><img src='" + src + "' /></span>" +
"</a>";
else
result = "<span><img src='" + src + "' height='150px' border='0' /></span>";
And in the Controller from the the image path I produce the image and return it back to the caller
try
{
var file = new FileInfo(fullpath);
if (!file.Exists)
return string.Empty;
var image = new WebImage(fullpath);
return new ImageResult(new MemoryStream(image.GetBytes()), "image/jpg");
}
catch(Exception ex)
{
return "File Error : "+ex.ToString();
}
Read the image, convert it to byte[], then return a File() with a content type.
public ActionResult ImageResult(Image image, ImageFormat format, string contentType) {
using (var stream = new MemoryStream())
{
image.Save(stream, format);
return File(stream.ToArray(), contentType);
}
}
}
Here are the usings:
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using Microsoft.AspNetCore.Mvc;
Yes you can return Image
public ActionResult GetImage(string imageFileName)
{
var path = Path.Combine(Server.MapPath("/Images"), imageFileName + ".jpg");
return base.File(path, "image/jpeg");
}
(Please don't forget to mark this as answer)
From a byte[] under Core 3.2, you can use:
public ActionResult Img(int? id) {
MemoryStream ms = new MemoryStream(GetBytes(id));
return new FileStreamResult(ms, "image/png");
}

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